1. Field of the Invention
The present invention relates to a coupling suitable for the drinking fluid container and capable of picking up a necessary amount of fluid out of the flexible container while keeping the fluid sealed from outside.
2 Description of the Related Art
There has been already developed an automatic vending machine of the bag-in-box (or BIB) type wherein the flexible container (or pouch) made of flexible sheet or film and filled with drinking fluid such as coffee and fruit juice is transported in a box made of corrugated cardboard.
According to this automatic vending machine of the BIB type, its cost can be made low because the container is disposable, and it can be sanitary because fluid in the container can be sucked into a cup by a pump while keeping the fluid shielded from outside.
A coupling connected to the flexible container and then to the piping in the automatic vending machine to allow fluid in the container to be sucked into the cup under this shied state is disclosed by Japanese Patent Disclosure Sho 62-258288 and others.
The coupling disclosed in Japanese Patent Disclosure Sho 62-258288 comprises a female connector attached to the container and a male connector fitted into the female one. When the male connector is fitted into the female one, a hermetic seal bonded to the bottom of the female connector is broken by a tip formed at the front end of the male connector and the container is thus opened. When the male connector is further pushed into the female one, a valve body formed in an inner cylinder of the male connector is opened to communicate the container with a flow path in the male connector an when the male connector is pulled out of the female one, the valve body is closed to shied the inside in the piping, to which the male connector is connected, from outside and to prevent fluid remaining in the piping from flowing out of the male connector.
It is desirable in the case of the above-described coupling that fluid in the container can be shielded from outside every time only an amount of fluid needed is collected from the container into the cup.
In the case of the coupling disclosed in Japanese Patent Disclosure Sho 62-258288, however, the container is usually communicated with the piping through the male and the female connector until the male connector is detached from the female one after the former is connected to the latter. This makes it impossible to shield fluid in the container from outside. Fluid is thus allowed to return from the piping back into the container or bacteria are allowed to enter into the container, so that fluid in the container cannot be kept pure. Further, even when the sucking pump is stopped, fluid remaining in the piping is allowed to drop for a while because the container and the piping are left communicated with each other.
Still further, it happens sometimes that the hermetic seal cannot be broken because of its thickness.